sugar-toolkit-gtk3/src/sugar3/graphics/style.py

# Copyright (C) 2007, Red Hat, Inc.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.

'''
The style module defines constants for spacing and sizing, as well as classes for 
Colors and Fonts. Text rendering is handled by Pango and colors are inputted by their
HTML code (e.g. #FFFFFFFF)

All the constants are expressed in pixels. They are defined for the XO screen
and are usually adapted to different resolution by applying a zoom factor.
'''

import os
import logging

from gi.repository import Gdk
from gi.repository import Pango
from gi.repository import Gio


FOCUS_LINE_WIDTH = 2
_TAB_CURVATURE = 1
ELLIPSIZE_MODE_DEFAULT = Pango.EllipsizeMode.END


def _compute_zoom_factor():
    '''
    Calculates zoom factor based on size of screen. 
    Returns double representing fraction of maximum possible screen size
    '''
    try:
        scaling = int(os.environ.get('SUGAR_SCALING', '100'))
        return scaling / 100.0
    except ValueError:
        logging.error('Invalid SUGAR_SCALING.')

    return 1.0


class Font(object):
    '''
    A font defines the style of how the text should be rendered. 
    
    Args:
        desc (str): a description of the Font object
    '''
    def __init__(self, desc):
        self._desc = desc

    def __str__(self):
        '''
        Returns description of font
        '''
        return self._desc

    def get_pango_desc(self):
        '''
        Returns Pango description of font
        '''
        return Pango.FontDescription(self._desc)


class Color(object):
    '''
    A Color object defines a specific color. 

    Args:
        color (str): String in the form #FFFFFF representing the color
        
        alpha (double):  transparency of color
    '''
    def __init__(self, color, alpha=1.0):
        self._r, self._g, self._b = self._html_to_rgb(color)
        self._a = alpha

    def get_rgba(self):
        '''
        Returns 4-tuple of red, green, blue, and alpha levels in range 0-1
        '''
        return (self._r, self._g, self._b, self._a)

    def get_int(self):
        '''
        Returns color encoded as an int, in the form rgba
        '''
        return int(self._a * 255) + (int(self._b * 255) << 8) + \
            (int(self._g * 255) << 16) + (int(self._r * 255) << 24)

    def get_gdk_color(self):
        '''
        Returns GDK standard color
        '''
        return Gdk.Color(int(self._r * 65535), int(self._g * 65535),
                         int(self._b * 65535))

    def get_html(self):
        '''
        Returns string in the standard html Color format (#FFFFFF)
        '''
        return '#%02x%02x%02x' % (self._r * 255, self._g * 255, self._b * 255)

    def _html_to_rgb(self, html_color):
        '''
        Converts and returns (r, g, b) tuple in float format from standard HTML format (#FFFFFF).
        Colors will be in range 0-1
        
        Args:
            html_color (string): html string in the format #FFFFFF
        '''

        html_color = html_color.strip()
        if html_color[0] == '#':
            html_color = html_color[1:]
        if len(html_color) != 6:
            raise ValueError('input #%s is not in #RRGGBB format' % html_color)

        r, g, b = html_color[:2], html_color[2:4], html_color[4:]
        r, g, b = [int(n, 16) for n in (r, g, b)]
        r, g, b = (r / 255.0, g / 255.0, b / 255.0)

        return (r, g, b)

    def get_svg(self):
        '''
        Returns HTML formatted color, unless the color is completely transparent, in
        which case returns "none"
        '''
        
        if self._a == 0.0:
            return 'none'
        else:
            return self.get_html()


def zoom(units):
    '''
    Returns size of units pixels at current zoom level
    
    Args:
        units (int): size of item at full size
    '''
    return int(ZOOM_FACTOR * units)


ZOOM_FACTOR = _compute_zoom_factor()

DEFAULT_SPACING = zoom(15)
DEFAULT_PADDING = zoom(6)
GRID_CELL_SIZE = zoom(75)
LINE_WIDTH = zoom(2)

STANDARD_ICON_SIZE = zoom(55)
SMALL_ICON_SIZE = zoom(33)
MEDIUM_ICON_SIZE = zoom(55 * 1.5)
LARGE_ICON_SIZE = zoom(55 * 2.0)
XLARGE_ICON_SIZE = zoom(55 * 2.75)

if 'org.sugarlabs.font' in Gio.Settings.list_schemas():
    settings = Gio.Settings('org.sugarlabs.font')
    FONT_SIZE = settings.get_double('default-size')
    FONT_FACE = settings.get_string('default-face')
else:
    FONT_SIZE = 10
    FONT_FACE = 'Sans Serif' 

FONT_NORMAL = Font('%s %f' % (FONT_FACE, FONT_SIZE))
FONT_BOLD = Font('%s bold %f' % (FONT_FACE, FONT_SIZE))
FONT_NORMAL_H = zoom(24)
FONT_BOLD_H = zoom(24)

TOOLBOX_SEPARATOR_HEIGHT = zoom(9)
TOOLBOX_HORIZONTAL_PADDING = zoom(75)
TOOLBOX_TAB_VBORDER = int((zoom(36) - FONT_NORMAL_H - FOCUS_LINE_WIDTH) / 2)
TOOLBOX_TAB_HBORDER = zoom(15) - FOCUS_LINE_WIDTH - _TAB_CURVATURE
TOOLBOX_TAB_LABEL_WIDTH = zoom(150 - 15 * 2)

COLOR_BLACK = Color('#000000')
COLOR_WHITE = Color('#FFFFFF')
COLOR_TRANSPARENT = Color('#FFFFFF', alpha=0.0)
COLOR_PANEL_GREY = Color('#C0C0C0')
COLOR_SELECTION_GREY = Color('#A6A6A6')
COLOR_TOOLBAR_GREY = Color('#282828')
COLOR_BUTTON_GREY = Color('#808080')
COLOR_INACTIVE_FILL = Color('#9D9FA1')
COLOR_INACTIVE_STROKE = Color('#757575')
COLOR_TEXT_FIELD_GREY = Color('#E5E5E5')
COLOR_HIGHLIGHT = Color('#E7E7E7')

PALETTE_CURSOR_DISTANCE = zoom(10)

TOOLBAR_ARROW_SIZE = zoom(24)

MENU_WIDTH_CHARS = 60